This Google Earth feature may be old hat to some of you, but I only just discovered it a few days ago. I habitually use TPE (The Photographer's Ephemeris) to plan out trips to new locations for landscape photos, but it provides only lines and numbers instead of 3D visual information about sunlight. So I was pretty excited when I discovered that Google Earth has a 3D lighting option. You can use a slider to select the time of day, and GE will position the sun and cast shadows accordingly. It makes a great complement to TPE! A screen cap: I've tested it out once so far, and it was quite accurate. Gotta love it.